Where can i download the pretty little liars books for free?

i really want to read all the pretty little liars novels, and i can't seem to find good, legit PDF's online. does anybody have the good ones? not the ones that are all spaced out and not set up like a regular ebook would be. i need the ones that look like they were downloaded from itunes or amazon. i wouldn't be this picky, but i'm reading them on my ipod and i can't zoom in to see the words on the ones that are all over the internet. if anyone has good ones, i would greatly appreciate it! thanks!